Engineered wood types

blogtopia — Mon, 01 Jun 2009 08:09:27 +0000

I-joist
Glued laminated timber
Multilaminar veneer
Veneer-based
          o Plywood
          o Laminated veneer lumber (LVL)
          o Parallel strand lumber (PSL)
          o Stamina wood
          o Parallam
Parallel strand lumber

Particle-based
          o Oriented strand board (OSB)
          o Laminated strand lumber (LSL)
          o Waferboard
          o Particleboard (chipboard)
Fiberboard
          o Insulation board
          o SyrocoWood
          o Homasote (1909)
          o Masonite (1924)
          o Medium-density fiberboard (MDF)
          o Hardboard
Mineral-bonded particleboard and fiberboard
          o Cement board
          o Fiber cement siding
          o Gypsum board
          o Papercrete
Strawboard
Wood-plastic composite

I-joist

blogtopia — Mon, 01 Jun 2009 08:03:18 +0000

An engineered wood joist, more commonly known as an I-joist is a product designed to eliminate many of the problems that occur with using conventional wood joists. Invented in 1969, the I-joist is a man made engineered wood product which has incredible strength in relation to its size and weight. The biggest notable difference, other than their look, compared to dimensional lumber is that the I-joist is designed to carry heavy loads over long distances while using less lumber than a dimensional solid wood joist of a size necessary to do the same task. As of 2005, approximately 50% of all wood light framed floors were framed using I-joists.

An I-joist comprises two main parts, the web and flange. The web is sandwiched between a top and bottom flange, creating the “I” shape. The flange can be made from laminated veneer lumber or solid wood finger-jointed together for ultimate strength. It is then grooved on one side to receive the web.

The web is typically made from plywood, laminated veneer lumber, or oriented strand board. After cutting the webs and flanges to the specified widths and lengths, they are assembled with waterproof glue by pressuring the web into the top and bottom flange. After initial assembly, the I-joist is then end-trimmed and allowed to cure in an oven at room temperature to approximately equilibrium moisture content. The sizes manufactured vary on the I-joists intended load and span. Their depths can range from 9 ¼ inches to 24 inches and are available up to 80 feet long. The intended use for an I-joist is for floor joists and roof rafters in both residential and commercial construction.

I-joists were designed to help eliminate typical problems that come with using solid lumber as joists. The advantage of I-joists is they will not bow, crown, twist, cup, check, or split as would a dimensional piece of lumber. Also, I-joists are designed to help eliminate squeaky floors by being more dimensionally sound and little to no shrinking. Although the I-joist may seem like a perfect choice as a building material, if it is installed incorrectly or altered the I-joist can fail. By reading the manufacturer’s instructions with the I-joist, most mistakes can be caught in advance.

The most common mistake typically is with subcontractors misplacing or improperly sizing holes in the web. Doing so can greatly compromise the strength of the joist and the ones around it potentially leading to structural failure in those joists. Some of common mistakes made with installing I-joists are: cutting or chiseling flange in any way, improperly sized joists hangers, improper nailing into rim joist and joist hangers, and wrong sized nails.

Source: Wikipedia

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Engineered wood types

I-joist

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